An Energy-Efficient and Reliable Scheduling Strategy for Dynamic WBANs With Channel Periodicity Exploitation

In dynamic scenarios such as walking, wireless body area networks (WBANs) have unique dynamic features, for instance, the sensor nodes placed on the limbs have approximately periodic link qualities. To realize energy-efficient and reliable communication in dynamic WBANs, this paper focuses on designing a scheduling strategy, that exploits the dynamic channel periodicity. In walking scenarios, we first construct a WBAN testbed, then conduct experiments to show the channel periodicity between the sensor nodes deployed at different positions and quantify the correlation between the received signal strength indication (RSSI) and the acceleration signals. Next, we propose a gait cycle detection algorithm to detect the periodic motion and calculate the acceleration periodicity and phase. Then, we propose a channel periodicity based scheduling (CPBS) strategy that exploits the periodic fluctuations of link qualities, to improve energy efficiency and reliability. With the CPBS strategy, the transmission time is allocated according to the motion state and the rate requirement of each sensor node, which can avoid channel collision. Finally, we evaluate the performance of the CPBS strategy in both periodic and realistic (approximately 23% of the time for aperiodic movements) scenarios. The results show that, compared to stochastic scheduling (SS) strategy, the proposed CPBS strategy can save 17.61% and 13.56% energy consumption in periodic and realistic scenarios, respectively. In addition, the packet loss rate (PLR) can be made as low as zero in both scenarios. Therefore, the proposed CPBS strategy can achieve energy-efficient and reliable communication in dynamic WBANs.